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A newly-published study has challenged the basis of a new and widely accepted theory in neuroscience. At issue is the process of neurogenesis, or the growing of new neurons, which was long believed to cease in humans shortly after birth. Over the past 30 years, however, researchers found increasing evidence suggesting neurogenesis does in fact occur in adult humans, and it is now widely believed to occur in two specific regions of the brain. This acceptance led researchers across the field to reexamine their theories and evidence for roles neurogenesis might play in learning, memory, dementia, and other concepts. Because adult neurogenesis implicates a variety of issues in neuroscience, the new study could be of great significance if its conclusions are correct.

The researchers found that while neurogenesis does occur in the adult brain, it occurs at such a low rate that it does not contribute noticeably to any neurological pathology. The study measured the levels of three proteins in the preserved brains of persons who had died at various ages ranging from infancy to 59 years. Two of the proteins are found in cells as they multiply, and the third occurs only in still-developing neurons. The researchers compared the protein levels with age, and found that neurogenesis rates decline with age more rapidly than in other mammals, meaning that the rate of neurogenesis adult brain is “functionally insignificant.”

Publication of the paper is forthcoming in the journal Neuropathology and Applied Neurobiology. A more in-depth commentary can be found at Neuroskeptic.